如何在python中的空行和单独行之间只保留一个空行？

import re

def remove_extra_blank_lines(code):
    pattern = r'\n\s*\n'
    return re.sub(pattern, '\n\n', code)

# 示例用法
code = '''
import os


def hello():
    print("Hello, world!")


def goodbye():
    print("Goodbye, world!")


hello()


goodbye()
'''

new_code = remove_extra_blank_lines(code)
print(new_code)

import os

def hello():
    print("Hello, world!")

def goodbye():
    print("Goodbye, world!")

hello()

goodbye()

def remove_extra_blank_lines(code):
    lines = code.split('\n')
    new_lines = []
    for i in range(len(lines)):
        if i < len(lines) - 1 and lines[i].strip() == '' and lines[i+1].strip() == '':
            continue
        new_lines.append(lines[i])
    return '\n'.join(new_lines)

# 示例用法与上述相同